Biopolymer-Based Injection into Cracked Soil Mass: Evaluation of Workability, Shrinkage, and Bonding Performance

This study presents the development and optimization of a biopolymer-based injection mixture for sealing desiccation cracks in soils. Mixtures incorporating kaolinite clay, xanthan gum, ordinary Portland cement, graphite particles, and a polycarboxylate-based superplasticizer were evaluated to assess workability, shrinkage behavior, and bonding performance. A systematic experimental program, including flow table tests, linear shrinkage measurements, and crack injection trials, was conducted to examine the influence of key constituents on rheological and dimensional stability. Results show that superplasticizer dosage strongly influences water demand and shrinkage, enabling reduced water content while maintaining target flowability. In contrast, xanthan gum and cement contents increased water demand, leading to greater shrinkage, underscoring the importance of careful optimization. The identified optimum mixture was successfully injected into cracks formed in natural soil under controlled conditions, highlighting its practical applicability. The findings contribute to advancing environmentally sustainable soil stabilization methods and reducing reliance on conventional cement-based practices.